1 files changed, 3 insertions, 0 deletions

diff --git a/src/alloc.c b/src/alloc.c
index c6fb2319d1e..9b84a7e51f8 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -2006,6 +2006,9 @@ mark_object (argptr)
         mark_object (&ptr->plist);
         XSETTYPE (*(Lisp_Object *) &ptr->name, Lisp_String);
         mark_object (&ptr->name);
+        /* Note that we do not mark the obarray of the symbol.
+           It is safe not to do so because nothing accesses that
+           slot except to check whether it is nil.  */
         ptr = ptr->next;
         if (ptr)
           {